Fall can be a downright gorgeous time to take a hike in a national park. The air is crisp, the bugs are gone, the crowds have vanished, and the landscape is gorgeous. Just don't forget that the bears are trying to put on some extra calories to get through the winter. And a hungry bear can be an ornery bear.

The folks at Yellowstone National Park put out a bear advisory the other day, and it's one that's applicable for other national parks in the northern Rockies. Basically, the message is to watch out for grizzlies trying to bulk up. Here's what they had to say:

Bears are out and active this time of year in the Greater Yellowstone area, including the Gallatin National Forest, Yellowstone National Park, the Beartooth Ranger District of the Custer National Forest, and state and private lands.

The National Forest, Yellowstone National Park, and Montana Fish, Wildlife & Parks join in urging visitors who use these areas to practice the tips and guidelines outlined by the Be Bear Aware campaign.

This time of year, bears are in constant search of food before denning for the winter. Bears are moving up and down in elevation and moving along river valley bottoms looking for calories—fruits and vegetables, unsecured food in residential areas (pet food, garbage, bird feeders), and carcasses from hunter harvests. Hikers, campers, hunters—all recreationists—should use care and be familiar with how avoid encounters in bear country.

Tips for recreating in bear country:

* Always carry bear pepper spray, have it close at hand, and know how to use it.

* If you are going to be alone in bear country, let someone know your detailed plans; better yet, don’t go alone.

* Be alert to signs of bear activity

* Think in advance about what you would do in the event of an encounter.

* Make noise as you travel.

* Cook any meals at least 100 yards from any backcountry campsites

* Store any attractants, including game carcasses, at least 100 yards from any backcountry campsites.

* Hunters: after making a kill get the carcass out of the area as quickly as possible; while field dressing, keep a can of bear pepper spray within easy reach; use special precautions if you must leave and return to a carcass, including placing the carcass where you can easily observe it from a distance when you return. Do not attempt to frighten away or haze a bear that is near or feeding on a carcass.

The Gallatin National Forest, Beartooth Ranger District on the Custer National Forest, and Yellowstone National Park require all attractants be stored appropriately. Unattended food, refuse, and attractants must be stored in hard-sided vehicles or bear-resistant containers, or be hung above the ground out of the reach of wildlife. Food, cooking utensils and garbage may not be left outside at any time unless in immediate use.

In Yellowstone National Park, regulations require visitors to stay at least 100 yards away from bears at all times.

For more detailed information on how you can be bear aware, please visit www.BeBearAware.org. Information on avoiding bear encounters can also be obtained at all Gallatin and Custer National Forests, Yellowstone National Park, and Montana Fish, Wildlife & Parks offices and visitor centers.